PALACE COUP: Artist Jeff Koons bought the home of the late "Bobo" Rockefeller (inset, with hubby Winthrop in 1948). Photo: Getty Images

For the first time ever, an artist has bought a Rockefeller.

Artist Jeff Koons, famed for his giant balloon-animal sculptures, has snatched up for an eye-popping $20 million a palatial Upper East Side townhouse from a member of the family renowned for its patronage of the arts, sources say.

The 10,000-square-foot mansion at 13 E. 67th St. was the longtime home of the late Barbara “Bobo” Rockefeller, who turned its lavish interior — with 19-foot ceilings, a squash court and a pool — into a must-visit stop on New York’s society circuit for decades.

But Koons has his work cut out for him, as the home has been vacant since 2005 and is in “complete disrepair,” sources said.

“It looked like a very ‘Gray Gardens’ type of place,” said a person who has recently been inside. “It’s a great place, but very run down.”

Koons, 55, whose works have sold for tens of millions of dollars, already owns the townhouse next door, which he bought last year for $12 million, but will need to do millions of dollars in renovations before he’d be able to join the two.

Rockefeller, who died at age 91 in 2008, was not typical of the family whose name is synonymous with old money and supporting the arts.

A coal miner’s daughter born Jievute Paulekiute, Bobo married into the clan after meeting Winthrop Rockefeller — a future governor of Arkansas and brother of former New York Gov. Nelson Rockefeller — in 1948. Seven months later, the couple had a son, Winthrop Jr.

The marriage didn’t last, and their 1951 break-up became a tabloid dream. She accused Winthop of being a womanizing drunk with a vast collection of pornography.

“I want him to suffer the way he has made me suffer; as he has humiliated me before the world,” Bobo told reporters. “I intend to be a Mrs. Rockefeller until the day I die.”

Not only did she take the Rockefeller name, she walked off with a $5.5 million divorce settlement — then a record-setting sum — which she used to buy the mansion.